小児の聴覚失認の3症例

抄録

Three cases of auditory agnosia developed in childhood were reported.
The first case was a twenty-four-year-old man who was initially diagnosed as having profound deafness at the age of two and educated at a school for the deaf. The second case was a six-year-old girl diagnosed as having profound deafness at the age of two years and four months. The third case was a two-year-old boy who had been behaving as deaf after epileptic attack at the age of one year and seven months.
Two of the three cases were confirmed to have normal hearing for pure tones in their infancy, and the remaining one had a hearing impairment of approximately 35dB. However, despite of the recovery of deafness, the difficulty of understanding of the spoken words and the inability to recognize the environmental noises, musical sounds and melodies remained permanently. EEG was found to be abnormal in the three patients.
From the long-term observations of these cases, the following conclusion was drawn with regard to the diagnosis of auditory agnosia:
1) The hearing impairment observed in auditorily agnostic children must be proved not due to peripheral hearing losses, but of central origin.
2) Objective audiometries including cerebral evoked response audiometry, electrocochleography and brain stem evoked response audiometry are very helpful for the diagnosis.
3) Long-term observations are often needed to confirm the diagnosis.
4) EEG or radioneurological examinations are important to confirm brain dysfunction or brain damage which causes the disease.